1. Field of the Invention
The present invention relates to a color photographic processing method and, more particularly, to a color photographic processing method using a color developing solution having improved storage properties.
2. Description of the Prior Art
In photographic processing steps for obtaining color images from image-wise exposed silver halide photosensitive materials, it is well known in the color development step that indoaniline, indophenol or azomethine dyes are formed by the image-wise coupling of the oxidation product of aromatic primary amines with dye-forming couplers, so as to form a photographic image.
It is generally desirable to process these silver halide photosensitive materials in a short period of time. Various proposals have, therefore, been made for expediting color development. In particular, color developing solutions simultaneously using a black-and-white developer as a development accelerator are known as superadditive developing solutions. For example, 1-phenyl-3-pyrazolidone is known to have a very strong development accelerating effect.
The superadditivity of 1-phenyl-3-pyrazolidone is described by G. F. van Veelen, The Journal of Photographic Science, Vol. 20, pp. 94-106 (1972); and the like.
However, color developing solutions containing 1-phenyl-3-pyrazolidone are quite unstable, compared with developing solutions (or PQ developers) containing hydroquinone, in combination with hydroquinone, which is usually used for black-and-white development, or ordinary color developing solutions in which 1-phenyl-3-pyrazolidone is not used. It has, therefore, been desired to improve the storability of developing solutions, especially color developing solutions containing 1-phenyl-3-pyrazolidone to be used for commercial photographic processings.
As to this lack of stability, G. F. van Veelen, supra describes that 1-phenyl-3-pyrazolidone incorporated into a color developing solution deteriorates rapidly when exposed to air.
It has been a common practice in the photographic art to incorporate sulfites and hydroxylamine salts as anti-oxidants into color developing solutions containing aromatic primary amine color developers in order to prevent the developing capability of the solutions from being reduced due to aerial oxidation.
These anti-foggants are, however, quite unsatisfactory as a storage improving agent for color developing solutions containing 1-phenyl-3-pyrazolidone since they have only slight effects for color developing solutions of this kind. As a result, precipitates or scum is formed therein by the aerial oxidation of 1-phenyl-3-pyrazolidone per se, by a deterioration due to alkali hydrolysis, and by a decomposition of an intermediate product which has a green color and is formed by the reaction of the aerial oxidation products of 1-phenyl-3-pyrazolidone with aromatic primary amine color developers.
U.S. Pat. Nos. 3,615,503 and 3,823,017 have proposed the use of hydroxyalkenes and 2-anilinoethanol as antioxidants as substitutes for hydroxylamines. The compounds, however, do not provide any effects for color developing solutions containing 1-phenyl-3-pyrazolidone.
Ascorbic acid and its derivatives and hydroxylbenzenes are also known as antioxidants for color and black-and-white developing solutions, but these compounds inhibit color development in color developing solutions and, moreover, provide only slight effects for color developing solutions containing 1-phenyl-3-pyrazolidone, so that the formation of scum and precipitates can be prevented only to a slight extent.
It is also known to use sucrose as an antioxidant for black-and-white developing solutions containing hydroquinone or N-alkyl-p-aminophenol as a developing agent. Sucrose, however, does not provide any effects for color developing solutions containing 1-phenyl-3-pyrazolidone.